Electric machines are able to convert electricity to mechanical power such as an electric motor or reversely mechanical power to electricity such as a generator. Therefore, a rotor and a stator, whereby the rotor rotates relative to the stator by means of magnetic induction represent the essential components of an electric machine.
In terms of eased transportation and handling it is known to segment the rotor and/or the stator in segments of a circle, that is rotor and stator are built of several segmented parts which will be assembled to build a ring-like rotor- and/or stator-assembly.
Regarding the assembling of a stator comprising a stator yoke with several stator tooth forming slots for accommodating the stator windings, it is common to initially assemble the stator segments to build the stator ring and subsequently wind the stator windings around the stator tooth, so that they are located in the slots. Concerning stators with a so called double-layer configuration the windings are disposed in two layers, that is on top of each other, whereby each phase winding occupies a first, that is a bottom position in a stator slot with its outgoing portion and a second, that is a top position in a further stator slot with its returning portion. In other words, each slot accommodates an outgoing phase winding of a first stator winding in a bottom position and a returning phase winding of a further stator winding in a top position.
The assembling of such stators having a double-layer configuration as mentioned is cumbersome, time-consuming and non-effective. After a first phase winding has been installed in the slots of the stator yoke, it occupies a lower portion in a first slot by its outgoing portion and a top position in a second slot by its returning position, that is the bottom position of the second slot is blocked by the returning portion of the first phase winding, thereby inhibiting another outgoing portion of another phase winding to be easily installed in the bottom position of this slot.
However, attempts to solve these problems have been proposed in a segmentation of the phase windings, whereby the stator windings are constructed in two halves, which are installed in the slots of the stator yoke and subsequently connected at their end windings by means of bolts for instance. Yet, this assembly method is still time-consuming and therefore non-effective. Besides, the stator comprises an increased number of separate components.